The present invention relates to an oil-in-water type emulsion composition which comprises a fat or oil, water, a protein, and a carrageenan but is free from emulsifiers, and to a process for producing the same.
For keeping their emulsified state stable, the majority of conventional emulsions having an oil-in-water type emulsion structure contain one or more than one emulsifiers, such as glycerol fatty acid esters, glycerol acetic acid fatty acid esters, glycerol lactic acid fatty acid esters, glycerol succinic acid fatty acid esters, glycerol diacetyltartaric acid fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, sucrose acetic acid isobutyric acid esters, polyglycerol fatty acid esters, polyglycerol condensed ricinoleic acid esters, propylene glycol fatty acid esters, stearoyl calcium lactate, stearoyl sodium lactate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monoglyceride, in their systems.
For the case where the use of an emulsifier alone is unable to bring out the intended physical properties, a number of attempts to solve such problem through the use of the emulsifier in combination with a stabilizer such as a polysaccharide thickener, a salt, and a pH adjuster have been made.
One example of such attempts is a process for producing a foamable oil-in-water type emulsion composition being a combination of a polyglycerol fatty acid ester, a polysaccharide thickener such as xanthan gum and xcex-carrageenan, and an lipophilic processed starch (Japanese Patent Laid-Open Application No. 6-225720).
However, a problematic aspect of the addition of emulsifiers, including those mentioned above, is that their own taste and smell spoil the original flavor of food.
Furthermore, in recent years, there is such a strong, society-wide preference for foods that are more natural as is typified by a tendency for consumers to prefer foods that are free from synthetic emulsifiers and show more naturally emulsified state, and it is expected that this tendency will further continue growing.
Under the circumstances, the technique recited in the patent publication mentioned above in which the use of a polyglycerol fatty acid ester as an essential and indispensable component for bringing out the intended physical properties is a prerequisite does not meet the demand.
Although there exist techniques that relate to oil-in-water type emulsion compositions that contain protein but are free from emulsifiers as mentioned above, problems in terms of emulsion stability against physical stresses, such as modification of protein by heating or freezing and destruction of emulsified state by stirring or kneading, remain to be solved. Particularly, in the case of the use of a solid fat, there arises, for example, the problem that its crystal growth with time exerts a large influence on the emulsified state and emulsion stability of the resulting emulsion composition.
For such reasons, realization of an oil-in-water type emulsion composition which keeps its emulsified state firm and stable even without the aid of an emulsifier has strongly been desired.
Thus, it is an object of the present invention to provide an oil-in-water type emulsion composition which shows, even without an emulsifier, high emulsion stability against such physical stresses as heating, freezing, stirring, kneading, etc.
The present invention achieved the above-described object by providing an oil-in-water type emulsion composition which is characterized in that it comprises a fat or oil, water, a protein, and a carrageenan but is free from emulsifiers.
Hereinafter, the oil-in-water type emulsion composition of the present invention will be described in further detail.
Although there is no particular restriction as to the oil or fat to be used in the present invention, examples thereof are a variety of vegetable and animal fats and oils typified by palm oil, palm kernel oil, coconut oil, corn oil, cotton seed oil, soybean oil, rapeseed oil, rice oil, sunflower oil, safflower oil, beef tallow, milk fat, lard, cacao fat, fish oil, and whale oil; and processed ones thereof obtained through one or more than one treatment steps selected from hydrogenation, fractionation, and transesterification. In the present invention, these oils and fats can be used either alone or in combination.
The amount of the fat or oil incorporated in the oil-in-water type emulsion composition of the present invention is preferably 4 to 85% by weight (hereinafter, abbreviated as xe2x80x9c%xe2x80x9d), more preferably 4 to 70%, much more preferably 4 to 50%.
Although there is no particular restriction as to the protein to be used in the present invention, examples thereof are whey proteins such as xcex1-lactalbumin, xcex2-lactoglobulin, and serum albumin; casein and other lactoproteins; low-density lipoproteins; high-density lipoproteins; egg proteins such as phosvitin, livetin, phosphoglycoprotein, ovalbumin, conalbumin, and ovomucoid; wheat proteins such as gliadin, glutenin, prolamine, and glutelin; and other animal and vegetable proteins. One or more than one of these proteins that can be employed in the present invention, or a food material containing one or more than one of these proteins, may be added to the composition, depending on the purpose.
Among the proteins listed above, the use of one or more than one proteins selected from whey proteins such as xcex1-lactalbumin, xcex2-lactoglobulin, and serum albumin, and casein, or the use of a food material containing one or more than one of these proteins is preferred.
The protein content of the oil-in-water type emulsion composition of the present invention is preferably 0.05 to 15%, more preferably 0.05 to 10%.
Examples of the carrageenan which is used in the present invention are xcexa-carrageenan, xcex-carrageenan, "igr"-carrageenan, xcexc-carrageenan, xcexd-caffageenan, xcex8-cafageenan, "xgr"-carrageenan, xcfx80-carrageenan, and xcex2-carrageenan. The carrageenan to be used in the present invention is one containing at least one or more of these.
Typical algae as a raw material from which the carrageenans mentioned above are derived are those of the genus Hypnea of the family Hypneaceae, the genus Eucheuma of the family Solieriaceae, the genus Chondrus of the family Gigartinaceae, the genus Gigartina, the genus Iredaea, and others. Of the above-mentioned carrageenans that can be used in the present invention, for example, algae of the genus Hypnea, the genus Eucheuma, the genus Chondrus, and the genus Iredaea are high in xcexa- and xcexc-carrageenan content. Moreover, algae of the genus Iredaea, the genus Gigartina, and the genus Chondrus are high in xcex- and xcex8-carrageenan content. Algae of the genus Eucheuma are high in "igr"- and xcexd-carrageenan content. The carrageenan to be used in the present invention is a crude extract derived from any of these raw material, algae or its refined product.
Of the carrageenans mentioned above, preparation of the oil-in-water type emulsion composition using a carrageenan containing a carrageenan(s) other than xcexa-carrageenan is preferable because the stability of the resulting emulsion against physical stresses such as stirring is improved.
xcexa-carrageenan has the characteristic of forming a tough brittle gel with low elasticity in an aqueous solution. Especially, such tendency becomes apparent particularly in a system in which monovalent cations such as potassium ions, rubidium ions, and cesium ions are present, resulting in the formation of a tougher and more brittle gel.
In contrast to the oil-in-water type emulsion composition of the present invention being in a stably emulsified state, the reason why an oil-in-water type emulsion composition prepared using a carrageenan composed of xcexa-carrageenan alone is poor in emulsion stability could be assigned to the gelling properties xcexa-carrageenan possesses, but the details are not known.
Therefore, preferred as the carrageenan to be used in the present invention is one that contains a carrageenan other than xcexa-carrageenan, such as carageenans containing at least one or more carrageenans selected from xcex-carrageenan, "igr"-carrageenan, xcexc-carrageenan, xcexd-carrageenan, xcex8-carrageenan, "xgr"-carrageenan, xcfx80-carrageenan, and xcex2-carrageenan. More preferably, the carrageenan to be used in the present invention is one containing at least one or more carrageenans selected from xcex-carrageenan, xcex8-carrageenan, and xcexd-carrageenan. Much more preferred is a carrageenan containing at least either xcex-carrageenan or xcex8-carrageenan. Most preferred is a carrageenan containing xcex-carrageenan.
The amount of the carrageenan contained in the oil-in-water type emulsion composition of the present invention is preferably 0.005 to 3%, more preferably 0.01 to 1%.
The oil-in-water type emulsion composition of the present invention comprises the fat or oil, protein, and carrageenan described above, and water. The water content of the oil-in-water type emulsion composition of the present invention is preferably 15 to 95%, more preferably 30 to 95%.
Particularly preferred as the oil-in-water type emulsion composition of the present invention is one comprised of 4 to 85% by weight of the fat or oil, 0.05 to 15% by weight of the protein, and 0.005 to 3% by weight of the carrageenan.
The reason why the oil-in-water type emulsion composition of the present invention can keep its emulsified state stable without an emulsifier is probably because the interaction between the protein and the carrageenan in the system (in the composition) takes part in the emulsification, but the details are not known.
If necessary, to the oil-in-water type emulsion composition of the present invention may be added the following components.
Sugars and sugar alcohols, starch, flour, inorganic salts and organic acid salts, gelling agents other than carrageenan, dairy products, egg products, cacao and cacao products, coffee and coffee products, and other various food materials; flavoring agents such as aromatizing agents and condiments; colorants; preservatives; antioxidants; pH adjusters; etc.
In the oil-in-water type emulsion composition of the present invention, the total content of these components is preferably 80% or less.
The oil-in-water type emulsion composition of the present invention can be used as an oil or fat kneaded into whipping cream, coffee whiteners, ice cream, soft ice cream premixes, bread, sweets, ham, sausages, and other processed foods, and is applicable for use in mayonnaise, dressings, cheese-like products, flour pastes, fillings, toppings, sandwich cream, spreads, etc.
The oil-in-water type emulsion composition of the present invention is produced by adding a protein to an aqueous phase and/or an oil phase, adding a carrageenan to the aqueous phase and/or the oil phase, and emulsifying the resulting aqueous and oil phases. In the process, in terms of workability, it is preferred that the carrageenan is added to the oil phase.
If necessary, the oil-in-water type emulsion composition of the present invention thus obtained may be homogenized by a homogenizing apparatus such as a valve-type homogenizer, a homomixer, and a colloid mill under a pressure of from 0 to 800 kg/cm2. Moreover, if needed, the emulsion composition may be heat-sterilized or subjected to heat-sterilization treatment through, for example, UHT-, HTST-, or batch-treatment, in which the emulsion composition is directly heated by injection or infusion of steam, or indirectly heated by means of a plate-, tube-, or scraped surface heat exchanger. The emulsion composition may be heat-sterilized in a retort or by microwave heating, or cooked over a flame. If necessary, the emulsion composition may be rehomogenized. If necessary, the emulsion composition may be subjected to cooling operation such as quick cooling and gradual cooling. Moreover, if necessary, the emulsion composition may be aged.
Furthermore, if necessary, the oil-in-water type emulsion composition of the present invention thus obtained may be stored under refrigeration or in a frozen state.
Hereinafter, the present invention will be described in further detail with reference to Examples and Comparative Examples, but these should by no means be construed as defining the scope of the present invention.